Removed MainPacket (was before used as a container for
MultimediaDataPackets but will not be needed when data is saved into
mySQL database.
When the server gets an IdentityPacket from the mobile device and the
state of this device is DONE a new Thread (SendRemainingPackets) is
started to send all the remaining packets the device didn't get because
of a disconnect. (Note that there can exist more then one job with state
done, this should be fixed in the future)